Self contained electric knife sharpener



Dec. 17, 1935. c. HOBART ET AL SELF CONTAINED ELECTRIC KNIFE SHARPENERFiled April 5, 1934 Q 4 A 4 .B [k ,V 5 a 9 4 7 a y y y g 8 4 5 S Rmzmv OE E TBL N No .WR E V .HCT mam T i M M wKw Patented Dec. 17, 1935 UNlTEDSTATES PATENT OFFICE,

SELF CONTAINED ELECTRIC KNIFE SHARPENER.

Louis C. Hobart, Southington, Conn, and Kenneth F. Lees, New York, N.Y., assignors to The Olympic Industrial Corporation,

New

This invention relates to electrically operated knife sharpeners. It isone of the principal objects of the invention to provide a device ofthis kind that is a complete, self-contained, unit furnishing fromwithin itself the energy required for its operation. Another-object isto make possible in a mechanism of this kind, the use of standard smallbattery cells. A further object is to provide in a device of this kindnovel means for imparting reciprocating motions to its sharpeningmembers. A still further object is to make the device readily adaptablefor economic manufacture. Still another object is to secure in a deviceof this kind by means of its particular construction maximum power withminimum current drain for a longer possible life of the battery cells.Further objects will become apparent in the following specificationandthe accompanying drawing in which a preferred embodiment of theinvention is shown.

In the drawing,

Fig. l is a longitudinal vertical sectional view of the sharpener;

Fig. 2 is a vertical sectional view along the plane of line 2-2 in Fig.1;

Fig. 3 is a partially cut-away bottom view of the sharpener with itsenergizing mechanism and its bottom closure plate removed;

Fig. 4 is a plan view of the sharpening members proper shown in anengaging position;

Fig. 5 is a perspective view of one of the sharpening members; and

Fig. 6 is a wiring diagram indicating the electrical connections betweenthe principal component parts of the sharpener.

Like characters of reference denote similar parts throughout the severalfigures and the following specification.

I0 is a housing, preferably made of bakelite or other suitable material,consisting of a substantially rectangular base portion II, and a topportion l2, superimposed upon the base portion II, also rectangular inshape. The base portion is open at its bottom and closed by a platev I3suitably secured to the housing by means of screws. The top portion l2has a substantially square opening 14 at its uppermost surface,extending somewhat down its sides in the shape of a V at I.

Attached to the inside of the housing H1, at the top of the baseportion. II, and secured thereto by screws, is a support plate I 8, itsends fitted, preferably, into recesses I! at the inside of the housing.I8 is a rectangular coil cage riveted to the support plate I 8 andprojecting into the top portion I2 of the housing II). This cage l8which is preferably made of sheet metal has one end closed at I9. 20 isa central core fastened to the end l9 having a coil 2| wound around it,a washer 22 holding the coil in place 5 upon the core.

Secured to the top of the cage IB- is a plate 23, having upturned andoutwardly extending cars 24 at its four corners, perforated to receivefulcrum pins 25 and 2B. The sides of the plate 23 10 have upturnedextensions 21 which project through opening [4 of the housing and areprovided with V-shaped notches 28 the bottom of which are slightlyhigher than the bottom of the V shapes [5 at the sides of the housingand-15 thus serve as a protection therefor. Imme diately adjacent andbetween the ears 24 at one end of the plate 23 are two down-turned lugs29 to which is fastened a fibre plate 30 supporting in its center a makeand break member 3| 20 having a contact pin32.

33 is a substantially rectangular plate having upturned lugs 34 at bothsides near its top perforated to fit over fulcrum pin 25 and thusprovide a swinging flapper having a pin 35 adapted 25 to contact withthe contact point 32 of the make and break member 3| which is disposedbetween the flapper and the cage l8 of the coil. Angularly extendingaway from the plate 33 towards the opening l4 of the housing and betweenex- 30 tensions 21 is a leg 36 being preferably an integral part of theplate. A substantially Z- shaped housing 31 on top'and at the end of theleg 36 is secured thereto, preferably by screws, and holding within it asharpening member 38. The member 38, made of suitable abrasive material,is preferably flattened at its top and bottom at 39 to be securely heldby the housing 31 on top of the leg 36, while its sides are slightlycurved symmetrically at 40 and provided with 40 recesses 4|, so thatprojections 42 and recesses 4| alternate with each other, as clearlyshown in Figs. 4 and 5.

Over the open end of cage I8 is disposed a rectangular plate 43, similarto plate 33 which 45 also similarly has upturned lugs 44 at both sidesnear its top perforated to fit over fulcrum pin 26 and thus provide aswinging armature at this end of the cage. Angularly extending away;

from the plate 43 towards the opening [4 of the 50 7 housing and betweenextensions 21 is a leg 45 being preferably an integral part of plate 43and symmetrically disposed with respect to leg 36 of plate 33. To theend of the leg 45 is secured a housing 31 holding a sharpening member 336| "make and break member.

identical with one having correspondingly numbered parts fastened to leg33. It will be noted that the two sharpening members engage each otherso that projections 42 of one member extend into recesses 4| of theother member as shown in Fig. 4.

The bottom of plate 33 terminates in a hooklike extension 33a and thebottom of plate 43 in a similar extension 48a both of which areconnected by a narrow strip 48. Support plate I6 is bent downwardly atright angles at lia to have fastened thereto one end of a retractilespring 41, the other end of which is fastened to extension 33a, thusurging the plate 33 towards the coil 2|. The support plate I8 is furtherextended towards the plate 43' at I61), and is provided with an openingI60 through which the extension 45a projects thus limiting its movement.

In the enlarged base portion ll of the housing ID are disposed two rowsof standard battery cells 48. While in each row are shown two cells,this number may obviously be varied. A dividing strip 49 of insulatingmaterial is placed longitudinally across =the portion ll of the housing,separating the two rows of cells. 50 are metal springs riveted to-bothsides of the strip 49, bent at right angles thereto near one of itsextreme ends. These springs contact with the central electrode of one ofthe battery cells on one side and with the bottom of one of the cells onthe other side of the strip thus electrically connecting the cells ofadjacentrows in series,

as is shown in dotted lines in Fig. 3. BI is a flat' spring placed overthe center of the strip 43 serving to keep the cells in position.

82 is a switch button through the top wall of the enlarged base portionll 01 the housing l8, having an enlarged head 53 within the base,resting upon a flat spring member 84 which is fastened to the strip 49near one end thereof opposite the one near which springs 50 arefastened. A spring 50a, similar to one of the springs 58,

is located immediately below spring member '54,

not in contact therewith, however, but adapted to'contact with thebottom of one of the battery cells in one row, while another similarspring b extends at the opposite side of the strip 49 to contact withthe central electrode of one of the cells in the other row, the spring53b being insulated from spring 501;. A portion of spring 88b isextended at 58c upwardly somewhat along strip 49, terminating below flatspring member 84 and normally in spaced relation therewith. Pressingdown upon the switch button 52 forces the spring member 54 into contactwith extension 580 of spring 50b, thus connecting electrically springs50a. and 50b. Immediately upon releasing the pressure upon button 52,this electrical connection is broken.

The wiring diagram in Fig. 6 clearly illustrates the electricalconnections and circuits. One end of the coil 2| is connected throughthe switch button 52 to spring 58b, cells 48 at one side, throughsprings 58 across the partition to the cells 48 at the other side,through spring 580 to the plate 33 and back to the coil through the Thecircuit is completed upon closing of the switch, by pressing the button52, and is kept closed so long as the button is pressed down. v

With the switch closed, the armature 43 is drawn to the coil and assumesthe position shown in Fig. 1, at the same time pushing the flapper plate33 away from the coil to the position shown by virtue of the connectionstrip 48. In this extreme position of the flapper, contact is brokenbetween the pin 38 and the contact point 32 of we make and break member3| when the retractile spring 41 draws the flapper plate 5 towards thecoil, while strip 48 forces the armature 43 away from the coil, untilthe armature reaches the limit of its travel away from the coildetermined by contact of the extension 48a with the wall of the slot liein support plate 10 extension lib. In that position, the flapper plate33 is again contacting with the make and break member 3| and the circuitbeing thus again closed, the armature 43 is again drawn towards the coiland the cycle of operation re- 15 peated. Both the flapper plate 33 andthe armature 43 being fulcrumed above the coil, this reciprocatingmovement is effected with very little power, and a rapid vibratorymovement is set up. By shielding the coil 2|, as shown, ago

path is provided for the lines of magnetic flux coming from the core atthe end nearest the flapper 33 to be carried back through the cage wallsto the armature side of the coil, thus exposing the armature to thegreatest possible as magnetic flux generally with a minimum of lossthereby increasing the power which is used to attract the armaturetoward the coil.

While the flapper plate 33 and the armature 43 are 'vibratorilyreciprocated as Just now exso plained, he angularly extending legs 33and 48 of, respectively, these two members, are also reciprocated.Attention is particularly drawn to the fact that plate 33 and leg 36 arefulcrumed around pin 29, while armature 43 and leg 45 are fulcrumedaround pin 26. Further, that while the armature 43 is moving towards thecoil at the center of the sharpener, the plate '33 is moved away fromit, and vice versa. By this means the extreme end of the leg 38 movesup- 46 wardly, while the extreme end of the leg 48 moves downwardly andthe sharpening members 38 held within housings 31. at these extreme endsof the legs, are reciproeated past each other in 'an opposite directionin arcuate paths having 45 fulcrum pins 25 and 26, respectively, astheir pivots. While the sharpening members are in such motion, thecutting edge of a knife to be sharpened is drawn across the oppositelydisposed faces of the sharpening members, when 50 ber 38 are providedwith the recesses and pro- 60 jections so that in case of wear, they caneasily be turned around and the life of the members greatly increased.Attention is particularly drawn to the fact that the symmetrical shapeof the, sharpening members make them invertible 65 as well as reversiblei. e. they can be changed so that their points of contact with the knifecan be varied to different positions, because they can be turned upsidedown and reversed laterally as well. The curvcd sides 40 are so shaped70 as to form segments of a. circle of a diameter much greater than thedistance between the opposite sides, whereby the abrasive action of themembers is equal to that of wheels having each a radius the same as thatof the curved 76 Drawing a knife in-this position a 55 sides 40 butoccupying much less space. The flat top and bottom on the sharpeningmember serves the purpose of providing a good clamping surface forholding the member within the housing and against the leg to which thehousing is fastened.

While we have shown a preferred form of the invention embodying itsprinciples, we do not wish to limit ourselves to the precise arrangement described and illustrated. We want it to be understood that variouschanges in the form, proportions and minor details may be resorted towithout departing from the principles or sacrificing any of theadvantages of the invention, as defined in the appended claims.

What we claim as new, is:

1. In a knife sharpener, sharpening members in juxta-positio'n to eachother and in continuous contact with opposite sides of the same cuttingedge of a knife placed between them, and

eleetro-magnetic means to move the said members alternately across saidsides in arcuate paths, the paths having their axes substantiallyparallel to the. said edge.

2. In a knife sharpener, as defined in claim 1, wherein each sharpeningmember is provided with curved sides having alternately projections andrecesses, the projections of one member fitting into the recesses of theother.

3. In a knife sharpener, as defined in claim 1, wherein each sharpeningmember is provided with a flat top and bottom and curved sides, onecurved side of one member adapted to contact with one curved side of theother member.

4. In a knife sharpener, as defined in claim 1, wherein the sharpeningmembers are invertible and reversible and provided with flat tops andbottoms and contacting curved sides.

5. In a knife sharpener, as defined in claim 1, wherein the sharpeningmembers are invertible and reversible and provided with flat tops andbottoms and contacting curved sides, the sides having alternatelyinterfitting projections and recesses. I

6. In a knife sharpener, an electro-magnet. an armature hingedlyfastened to one side of the magnet in circuit, therewith and a flapperplate hingedly secured to the other side, the said armature and platebeing connected to cause the one to move towards the magnet while theother moves away from it, a make and break member in the said circuit,sharpening members fastened, respectively, to the said armature and thesaid plate, and means to energize the said magnet causing vibratoryreciprocating travels of the said armature and said plate for actuatingthe said sharpening members.

7. In a knife sharpener, as defined in claim 6, wherein the make andbreak member cooperates with the said flapper plate, the said make andbreak member being disposed between the said magnet and said plate, anda shielding cage surrounds the magnet on all sides except the oneopposite the armature.

8. In a knife sharpener, as defined injclaim 6, wherein a shielding cagepartially surrounds the 5 magnet, a retractile spring to draw the saidplate towards the said cage and simultaneously move the said armatureaway therefrom, and means to limit the movement of the said armature. 1

9. In a knife sharpener, an electro-magnet, an armature hingedlyfastened to one side ofthe magnet and a flapper plate hingedly securedto the other side, the said armature and plate being connected to causethe one to move 5 towards the magnet while the other moves away from itand each having a leg angularly disposed to each other, sharpeningmembers carried by the said legs, a make and breakmember cooperatingwith the said flapper plate, and 20 means to energize the said magnetcausing vibratory reciprocating travels of the said armature and plate,whereby the said sharpening members are given oscillatory motions inopposite directions adapted to sharpen the cutting edge of a 25 knifeplaced between them.

10. In a knife sharpener, a housing, an electromagnet within thehousing, an armature hing-'- edly fastened to one side of the magnetand, a flapper plate hingedly secured to the other side, 30 a make andbreak member cooperating with the said flapper plate, the said armatureand plate being connected to cause the one to move towards the magnetwhile the other moves away from it and each having a leg angularly dis-5 posed to each other, sharpening members carried by the said legs,battery cells connected in series within the bottom of the housing, andmeans to energize the said magnet intermittently through the said makeand break member 40 causing vibratory reciprocating travels of the saidarmature and plate, whereby the said sharpening members are givenoscillatory motions in opposite directions to sharpen the cutting edgeof a knife placed between them.

11. In a knife sharpener, a housing having a large bottom portion and asmaller top portion. and an opening at its top, sharpening memberswithin the housing in juxtaposition to each other and at opposite sidesof the same cutting 5 edge of a knife placed between them through thesaid opening, battery cells within the said bottom portion, anelectro-magnet within the said smaller portion, a make and break memberin the field of the said magnet, and means to 5 close an electriccircuit between the magnet and the cells to oscillate the memberssimultaneously in opposite directions for sharpening the knife.

LOUIS c. HOBART. 6o KENNETH F. LEES.

